The term "Middle Ages" itself ultimately derives from the description of the period of "obscurity" in Italian history during the 9th to 11th centuries, the saeculum obscurum or "Dark Age" of the Roman papacy[1] as seen from the perspective of the 14th to 15th century Italian Humanists.

In the 11th century began a political development unique to Italy, the transformation of medieval communes into powerful city states modelled on ancient Roman Republicanism.
The republics of Venice, Florence, Genoa, Pisa, among others, rose to great political power and paved the way for the Italian Renaissance and ultimately the "European miracle", the resurgence of Western civilization from comparative obscurity in the Early Modern period. On the other hand, the Italian city states were in a state of constant warfare, adding to and overlapping with the persistent conflict between the Pope and the Holy Roman Emperor.
Each city aligned itself with one faction or the other, yet was divided internally between the two warring parties, Guelfs (loyal to the Pope) and Ghibellines (loyal to the Emperor). Since the 13th century, these wars had increasingly been fought by mercenaries, giving rise to the Italian institution of condottieri and the Swiss mercenary culture.
After the three decades of wars in Lombardy between the Duchy of Milan and the Republic of Venice, there was eventually a balance of power between five emerging powerful states, which at the Peace of Lodi formed the so-called Italic League, bringing relative calm for the region for the first time in centuries.
These five powers were the maritime republics of Venice and Florence, whose naval powers dominated the east and west coast of the peninsula, respectively, the territorial powers of Milan and the Papal States, dominating the northern and central parts of Italy, respectively, and the Kingdom of Naples in the south.

Transition from Late Antiquity (6th to 8th centuries)

Italy was invaded by the Visigoths in the 5th century, and Rome was sacked by Alaric in 410. The (traditional) last Western Roman Emperor, Romulus Augustus, was deposed in 476 by an Eastern Germanic general, Odoacer. He subsequently ruled in Italy for seventeen years as rex gentium, theoretically under the suzerainty of the eastern Roman emperor Zeno, but practically in total independence. The administration remained essentially the same as that under the Western Roman Empire, and gave religious freedoms to the Christians. Odoacer fought against the Vandals, who had occupied Sicily, and other Germanic tribes that periodically invaded the peninsula.

In 489, however, Emperor Zeno decided to oust the Ostrogoths, a foederatum people living in the Danube, by sending them into Italy. On February 25, 493 Theodoric the Great defeated Odoacer and became the king of the Ostrogoths. Theodoric, who had lived long in Constantinople, is now generally considered a Romanized German, and he in fact ruled over Italy largely through Roman personnel. The Goth minority, of Arian confession, constituted an aristocracy of landowners and militaries, but its influence over the country remained minimal; the Latin population was still subject to Roman laws, and maintained the freedom of creed received by Odoacer. The reign of Theodoric is generally considered a period of recovery for the country. Infrastructures were repaired, frontiers were expanded, and the economy well cared for. The Latin culture flourished for the last time with figures like Boethius, Theodoric's minister; the Italian Kingdom was again the most powerful political entity of the Mediterranean. However, Theodoric's successors were not equal to him.

The eastern half of the Empire, now centred on Constantinople, invaded Italy in the early 6th century, and the generals of emperor Justinian, Belisarius and Narses, conquered the Ostrogothic kingdom after years of warfare, ending in 552. This conflict, known as the Gothic Wars, destroyed much of the town life that had survived the barbarian invasions. Town life did not disappear, but they became smaller and considerably more primitive than they had been in Roman times. Subsistence agriculture employed the bulk of the Italian population. Wars, famines, and disease epidemics had a dramatic effect on the demographics of Italy.
The agricultural estates of the Roman era did not disappear. They produced an agricultural surplus that was sold in towns; however slavery was replaced by other labour systems such as serfdom.

The withdrawal of Byzantine armies allowed another Germanic people, the Lombards, to invade Italy. Cividale del Friuli was the first main centre to fall, while the Byzantine resistance concentrated in the coast areas. The Lombards soon overran most of the peninsula, establishing a Kingdom with capital in Pavia, divided into a series of dukedoms. The areas in central-northern Italy which remained under Byzantine control (mostly the current Lazio and Romagna, plus a short corridor between Umbria that connected them, as well as Liguria) became the Exarchate of Ravenna. Southern Italy, with the exception of Apulia, current Calabria and Sicily, were also occupied by the two semi-independent Lombard duchies of Spoleto and Benevento. Under the Imperial authority remained also much of the ports, which eventually turned into actually independent city-states (Gaeta, Naples, Venice, Amalfi).

Rise of the Patriarchate of Rome

The Church (and especially the bishop of Rome, by now styled the pope), had played an important political role since the time of Constantine, who tried to include it in the imperial administration.

In the politically unstable situation after the fall of the western empire, the Church often became the only stable institution and the only source of learning in western Europe. Even the barbarians had to rely on clerics in order to administer their conquests. Furthermore, the Catholic monastic orders, such as the Benedictines had a major role both in the economic life of the time, and in the preservation of classicalculture (although in the east the Greek authors were much better preserved).

After the Lombard invasion, the popes were nominally subject to the eastern emperor, but often received little help from Constantinople, and had to fill the lack of stately power, providing essential services (ex. food for the needy) and protecting Rome from Lombard incursions; in this way, the popes started building an independent state.

Early Middle Ages (8th to 9th centuries)

Collapse of the Exarchate

At the end of the 8th century the popes definitely aspired to independence, and found a way to achieve it by allying with the Carolingian dynasty of the Franks: the Carolingians needed someone who could give legitimacy to a coup against the powerless Merovingian kings, while the popes needed military protection against the Lombards.

In 751 the Lombards seized Ravenna and the Exarchate of Ravenna was abolished. This ended the Byzantine presence in central Italy (although some coastal cities and some areas in south Italy remained under Byzantine control until the 11th century). Facing a new Lombard offensive, the papacy appealed to the Franks for aid. In 756 Frankish forces defeated the Lombards and gave the Papacy legal authority over all of central Italy, thus creating the Papal States. However, the remainder of Italy stayed under Lombard (such as Benevento and Spoleto) or Byzantine (such as Calabria, Apulia and Sicily) control.

The Frankish (Carolingian) Empire

In 774, upon a Papal invitation, the Franks invaded the Kingdom of Italy and finally annexed the Lombards; as a reward the Frankish king Charlemagne received papal support. Later, on December 25, 800, Charlemagne was also crowned emperor of the Holy Roman Empire by the pope, triggering controversy and disputes over the Roman name. A war between the two empires soon followed; in 812 the Byzantines agreed to recognize the existence of two Roman Empires in return for an assurance that the remaining Byzantine possessions in Italy would be uncontested.

Throughout this period, some coastal regions, and all of southern Italy, remained under Byzantine or Lombard control. The Imperial authority never extended much south of the Italian Peninsula. Southern Italy was divided amongst the two Lombards duchies of Spoleto and Benevento, who accepted Charlemagne's suzerainty only formally (812), and the Byzantine Empire. Coastal cities like Gaeta, Amalfi, Naples on the Tyrrhenian Sea, and Venice on the Adriatic Sea, were Latin-Greek enclaves who were becoming increasingly independent from Byzantium. A conquest of Benevento, otherwise, would have meant the total encompassment of the Papal territories, and probably Charlemagne thought it was good for his relationships with the Pope to avoid such a move. The age of Charlemagne was one of stability for Italy, though it was generally dominated by non-Italian interests. The separation with the Eastern world continued to increase. Leo III was the first Pope to date his Bulls from the year of Charlemagne's reign (795) instead of those of Byzantine emperors. This process of isolation from the Eastern Empire and connection with the Western world of France and Germany, which had started three centuries before, was completed at the beginning of the 9th centuries. Sicily, Calabria, Puglia and the marine cities were the main exceptions to this rule.[citation needed]

After the death of Charlemagne (814) the new empire soon disintegrated under his weak successors. The equilibrium created through the great emperor's charisma fell apart. This crisis was due also to the emergence of external forces, including the Saracen attacks and the rising power of the marine republics. Charlemagne had announced his division of the Empire in 806: the Lombard-Frank reign, together with Bavaria and Alamannia, was to be handed over to his son Pepin of Italy.

The first half of the 9th century saw other troubles for Italy as well. In 827, MuslimArabs known as Aghlabids invaded and conquered Sicily; their descendants, the Kalbids, ruled the island until 1053. In 846, Muslim Arabs invaded Rome, looted St. Peter's Basilica, and stole all the gold and silver in it. In response, Pope Leo IV started building the Leonine walls of the Vatican City in 847; they were completed in 853. In the late 9th century, the Byzantines and the Franks launched a joint offensive against the Arabs in southern Italy; however, only the Byzantines won any territory in that campaign.[citation needed]

Southern Italy

With Charlemagne's conquest of 774, the north of Italy was politically separated from the south completely. Though the Byzantines had continued to hold most of Apulia and Calabria and the Lombard duchies of the south had been aloof of Pavian policies for a century, the situation was exacerbated by the loss of a centralising Lombard authority in the north. Immediately, the duke of Benevento, Arechis II, proclaimed himself a sovereign prince and set about opposing Charlemagne's assumption of Lombard kingship.

Creation of independent moieties (774–849)

Under Arechis and his successors, it was the Beneventan policy to pay homage to the Carolingian emperors but ignore their rulings. As a result, De facto independence was achieved from Frankish as well as Byzantine authority. The Duchy of Benevento reached its territorial peak under Sicard in the 830s. At his time, the Mezzogiorno was suffering the ravages of the Saracens, against whom Sicard warred constantly. He also warred against his Greek neighbours, especially Sorrento, Naples, and Amalfi. It was in a war with Naples that Duke Andrew II first called in Saracenmercenaries.

In 839, Sicard was assassinated and a civil war broke out which illustrated the nature of political power in the south. It was still largely in the hands of the land-owning aristocracy, who had the power to choose a prince. In 839, some chose Radelchis I, the treasurer and assassin, and some chose Siconulf of Salerno, who was installed at Salerno. This civil war continued apace for a decade, during which the gastaldates of Benevento took the opportunity to entrench their independence, especially Capua, which sided with Siconulf. In 849, the Emperor Louis II, in one of his first acts as King of Italy, invaded the peninsula and imposed peace between the Lombard factions. He divided the principality into two: one at Benevento, one at Salerno. Thenceforward, the history of the Lombard south is one of declining, competing powers.

In the Tyrrhenian Greek cities, the violence raging inland, between them and their fellow Greeks on toe and heel, fostered the circumstances of de facto independence. Naples, in particular, had a history of differences with Byzantium and had in the past sought to make herself dependent on other authorities, often papal. In 801, the Byzantine patrician of Sicily succeeded in creating Anthimus duke. However, Anthimus was unable to control the cities under his rule, Gaeta and Amalfi. Subsequent to Anthimus, the patrician tried to appoint his own candidate without imperial approval. The people rebelled and accepted Stephen III in 821. During Stephen's decade of rule, Naples severed all legal ties to Constantinople and even began minting her own coins. In 840, after a brief flirtation with Frankish servitude, to Lothair I, and a Frankish duke, in the person of Duke Contard, the Neapolitan citizenry elected Sergius I their magister militum. Sergius established a dynasty, the Sergi, that was to rule the duchy for the next three hundred years.

In Gaeta, as in Naples, the violent situation inland required new power structures to maintain Byzantine authority. The Gaetans received their first imperial Byzantine hypati around the time of the Beneventan civil war. While the first hypati remained Byzantine loyals, in 866, the sudden appearance of a new dynasty under Docibilis I represented Gaeta's move from Byzantium towards independence. The first elected ruler of Amalfi was a prefect appearing in 839, simultaneous with the death of Sicard and the appearance of a Gaetan hyaptus. However, Naples, Gaeta, Amalfi, the Tyrrhenian cities, and Venice (in North Italy) retained some allegiance to Byzantium until the 11th century-long after becoming de facto independent.

Period of confusion (849–915)

The period following the Beneventan civil war was one of confusion, brought on by the independence movements in the various cities and provinces and by the Saracen onslaught. In Salerno, a palace coup removed Siconulf's successor Sico II in 853 and destabilised that principality until a new dynasty, the Dauferidi, came to power in 861.

In 852, the Saracens took Bari and founded an emirate there. Greek power being significantly threatened, as well as Adriatic commerce, the Byzantine emperor requested an alliance from Louis II of Italy. Similarly, the new prince of Benevento, Adelchis, an independent-minded ruler, also sought his aid. Louis came down and retook Bari in 871 after a great siege. Louis then tried to set up greater control over all the south by garrisoning his troops in Beneventan fortresses. The response of Adelchis to this action was to imprison and rob the emperor while he was staying the princely palace at Benevento. A month later, the Saracens had landed with a new invasive force and Adelchis released Louis to lead the armies against it. Adelchis forced Louis to vow never to re-enter Benevento with an army or to take revenge for his detention. Louis went to Rome in 872 and was released from his oath by Pope Adrian II on 28 May. His attempts to punish Adelchis were not very successful. Adelchis vacillated between nominal fealty to the Carolingian and Byzantine emperors, but, in fact, by his alterations to the Edictum Rothari, he acknowledged himself as the legitimate Lombard "king."

The successors of Adelchis were weak and the principality of Benevento declined just as Salernitan power was beginning to make itself felt. Guaifer of Salerno was on friendly terms with the Saracens, a habit which annoyed the popes and often put a ruler at odds with his neighbours. The south Italian lords continually rotating in their allegiances. Guaifer's successor, Guaimar I, made war on the Saracens. Guaifer had originally associated Guaimar with him as co-ruler, a practice which became endemic to the south and was especially evident in Capua.

The Kingdom of Italy and the Holy Roman Empire

The Holy Roman Empire

In 951 the thrones of Italy and Germany were united. The ruler of the new realm, Otto I, claimed that the union revived the empire of Charlemagne and received the title of Holy Roman Emperor in 962. The Emperor, or his subordinate ruler of the Kingdom of Italy, nominally controlled the Northern Italian communes. The papacy went through an age of decadence, which ended only in 999 when emperor Otto III selected Silvester II as pope.

Southern Italy

Under the Macedonian dynasty, Byzantine power experienced a recovery; and the impact of this was felt in southern Italy. During the late 9th century the amount of territory under direct Byzantine rule (which in the early 9th century was limited to the toe and heel of the peninsula) expanded dramatically. The Catepanate of Italy was set up to administer the newly acquired territory. The rest of Southern Italy remained divided among the Lombard kings and the Italian cities. Both sets of principalities were de facto independent, but paid nominal allegiance to Byzantium.

The Byzantine gains in the southern Italian mainland were, however, accompanied by setbacks in Sicily. In 878 the Arabs captured the crucial city of Syracuse, and by 902 the entire island was under Arab rule.[citation needed]

High Middle Ages (10th-13th Centuries)

The 11th century signalled the end of the darkest period in the Middle Ages. Trade slowly picked up, especially on the seas, where the Maritime Republics of Amalfi, Venice, Pisa, Genoa, Ancona and Gaeta became major powers. The papacy regained its authority, and started a long struggle with the empire, about both ecclesiastical and secular matters. The first episode was the Investiture Controversy. In the 12th century those Italian cities which lay in the Holy Roman Empire launched a successful effort to win autonomy from the Holy Roman Empire (see Lombard League); this made north Italy a land of quasi-independent or independent city-states until the 19th century (see Italian city-states and history of every city). The revolts were funded by Byzantium, which hoped to expel the Germans from Italy; this sponsorship was, like the invasion of the South, part of a 12th-century Byzantine effort to regain the influence it had held on the peninsula during the reign of Justinian.

In the 11th century, the Normansoccupied the Lombard and Byzantine possessions in Southern Italy, ending the six century old presence of both powers in the peninsula. The independent city-states were also subdued. During the same century, the Normans also ended Muslim rule in Sicily. Norman rule in what had once been Byzantine territory naturally angered Byzantium, which in 1155 made a last attempt under the EmperorManuel I Komnenos to reassert its authority in Southern Italy. But the attempt failed, and in 1158 the Byzantines left Italy.[citation needed]
Unlike the Norman conquest of England (1066), which took place over the course of a few years after one decisive battle, the conquest of Southern Italy was the product of decades and many battles, few decisive. Many territories were conquered independently, and only later were all unified into one state. Compared to the conquest of England, it was unplanned and unorganised, but just as permanent.

The Black Plague ravaged Europe during the 1340s-50s, wiping out almost half the continent's population. Particularly detrimental was the fact that most of the victims were young adults in their prime working years, which left behind an "hourglass" population structure comprised heavily of children and older people with fewer in-between. However, it should also be pointed out that the widespread belief of medieval Europe having a "pyramid" population where most people were under 45 was not completely true and in fact varied widely from region to region. France traditionally had high birth rates, but Italy's fertility was lower to begin with and especially after the Plague had ravaged the region, many cities such as Florence, Verona, and Arezzo had populations where more than 15% of people were over the age of 60. Since overall life expectancy in Europe did not increase by any significant margin during this period, the aging cohort in some areas can be almost completely blamed on the effects of the Plague. Finally, it should be pointed out that wealthy households had larger numbers of children than the poor. For example, in the early 15th century, the average age of Florence's population among the lower classes was 25 while the upper classes had an average age of just 17. The countryside became swiftly depopulated after the Plague as well due to surviving young people moving en masse to the cities.

The Italian Renaissance originates in 14th-century Tuscany, centered in the cities of Florence and Siena. It later had a great impact in Venice, where the remains of ancient Greek culture were brought together, providing humanist scholars with new texts. The Renaissance later had a significant effect on Rome, which was ornamented with some structures in the new all'antico mode, then was largely rebuilt by humanist 16th-century popes.

The Italian Renaissance peaked in the mid-16th century as foreign invasions plunged the region into the turmoil of the Italian Wars. However, the ideas and ideals of the Renaissance endured and even spread into the rest of Europe, setting off the Northern Renaissance, and the English Renaissance.